1. Technical Field of the Invention
The present invention is directed to a bead breaker device for detaching the bead of a tire from the corresponding rim of a wheel (rim and tire mounted) for automobiles, capable of operating in a wide range of sizes of the diameter of the rim of the wheel through simple operations.
2. Prior Art
As known, the assembly and disassembly of tires onto and from the respective rims is carried out through tire-dismounting machines that we shall avoid describing in greater detail hereafter since they are already known to men skilled in the art.
It is also known that so as to be able to carry out the dismounting of the tire, the bead, i.e. the reinforced edge of the tire, must first be detached from the bead-locking edge of the rim.
Said detachment operation is carried out through devices, known a bead breakers, which are generally arranged on the tire dismounting machines.
The bead breaking of a tire is carried out by a bead breaking tool, also known as a disc, which in a first step must apply a pressure force against the sides of the tire, in order to detach the corresponding bead portion, and in a second step it must penetrate into the rim positioning itself between the edge of the rim and the bead, in order to allow the complete bead breaking of the tire put into rotation.
Basically, the disc carries out the aforementioned two steps substantially taking up two configurations, for thrusting and penetration, respectively.
Known bead breakers are often equipped with systems for moving the disc that are extremely complex and expensive from the constructive point of view, like for example cylinder-piston groups and complex articulation systems that, when actuated, allow the disc to pass from the thrusting configuration to the penetration configuration and vice-versa.
Of course, the bead breaking operation must be carried out on the two opposite sides of each tire, and therefore the simplest known solution is that which foresees the wheel being tilted at the end of the bead breaking operation carried out on one side.
Unfortunately, this solution has numerous drawbacks, above all with wheels having a large diameter and/or large weight.
According to a solution of the prior art it is possible to foresee the use of two bead breaker devices operating on the respective sides of the tire.
Unfortunately, this solution also implies some drawbacks and disadvantages, since the constructive complexity is substantially duplicated with a substantial increase in costs.
Therefore, there is a strong requirement to have a bead breaker device that is simple to make and effective in use and that, through simple operations, can move the disc from the thrusting configuration to the penetration configuration and vice-versa.